Soap, powders, blue, etc.

According to What Jane Austen Ate and Charles Dickens Knew, clothing that has survived from the early 19th C. shows a "bluish hue of many of the colors." This was to counteract the yellow light given off by candles. Especially in the Regency period, white was the fashionable color for ladies gowns, so that bluish hue would be important. (I must add that Austenites have pointed out inaccuracies in the book, so I don't know how reliable this is.)

Then there are "blue haired ladies." Grey or white hair can take on a yellow cast. I have o idea of it's still available but in the middle of the last century, you could buy a blue hair rinse that would supposedly counteract the yellow. Unfortunately, it didn't always result in white hair, but instead made the hair distinctly blue. So "blue hair" became a synonym for "older woman," or "little old lady." Not necessarily a positive connotation.

Some washing powders had some specks of "blue" mixed in not so many years ago.
I also rermember these blocks of wonderful, intense "whitening blue".

"Indigo" is one of the high value goods,along with spices and tea, traded and transported in sailing ships especially during the European colonial period in the past few cenruries up to the early 20th century.
India was also an important producer of this product and since George Orwell lived and worked for a few years in old Burma(part of British administered India) he would be have seen the local and Indian "dobi wallas" using the stuff to whiten the white cotton clothes and bedsheets before drying them along grassy riverbanks in the hot noon day sun.

Come to think of it there are actually quite a few washing powders that contain small blue grains. Could be some sort of whitening or bleaching particles.

I once taught English to someone who worked for Proctor & Gamble and he confirmed that the specks in detergent are purely psychological to make people think that there are special active ingredients. He also revealed to me that the cheapest detergent sold at that time in France (Tide, which is no longer sold here) and the most expensive one (Ariel) were strictly identical but that Ariel outsold Tide 5 to 1.

The Mrs. Stewart's web site notes that at one time, many powdered detergents were blue, just to imply that they contained bluing.

Bluff!

At least one laundry blue brand has survived, even if their packaging design is still resolutely 1950s: feinstes Waschblau.

I would be rather reluctant to put that together with white laundry.

Is it bluish/bluing or blueish/blueing? Or just a regional variation?